Fully redundant linearly expandable broadcast router

ABSTRACT

A fully redundant linearly expandable router is comprised of first, second, third and fourth router components. Each router component includes first and second routing engines. First, second and third discrete links couple the first routing engine to the first routing engines, respectively. Fourth and fifth discrete links couple the first routing engine to the first routing engines, respectively. A sixth discrete link couples the routing engine to the routing engine. Seventh, eighth and ninth discrete links couple the second routing engine to the second routing engines, respectively. Tenth and eleventh discrete links couple the second routing engine to the second routing engines, respectively. A twelfth discrete link couples the routing engine to the router engine.

CROSS REFERENCE

This application claims the benefit, under 35 U.S.C. §365 ofInternational Application PCT/US03/18821, filed Jun. 13, 2003, which waspublished in accordance with PCT Article 21(2) on Dec. 31, 2003 inEnglish and which claims the benefit of United States provisional patentapplication No. 60/390,845, filed Jun. 21, 2002.

FIELD OF THE INVENTION

The present invention relates to broadcast routers and, moreparticularly, to a fully redundant linearly expandable broadcast routerhaving plural routing engines arranged in a fully connected topology.

BACKGROUND OF THE INVENTION

A broadcast router allows each one of a plurality of outputs therefromto be assigned the signal from any one of a plurality of inputs thereto.For example, an N×M broadcast router has N inputs and M outputs coupledtogether by a routing engine which allows any one of the N inputs to beapplied to each one of the M outputs. Oftentimes, it is desirable toconstruct larger broadcast routers, for example a 4N×4M broadcastrouter. One solution to building larger broadcast routers was to use thesmaller broadcast router as a building block of the proposed largerbroadcast router. This technique, however, resulted in the exponentialgrowth of the proposed larger broadcast routers. For example; toconstruct a 4N×4M broadcast router required 16 N×M broadcast routers. Asa result, large broadcast routers constructed in this manner were oftenboth expensive and unwieldy. Linearly expandable broadcast routersovercame the problems of geometric expansion. However, conventionallyconfigured linearly expandable broadcast routers suffer from other typesof deficiencies. For example, oftentimes, they are susceptible tocatastrophic failures which cause plural broadcast router components tofail in response to a single break.

SUMMARY OF THE INVENTION

A fully redundant linearly expandable router is configured to includethree or more router components, each of which includes first and secondrouting engines. The first routing engines of the three or more routercomponents are arranged in a first fully connected topology whereby aninput side of each one of the three or more first routing enginesincludes a discrete link to an input side of each one of the remainingones of the three or more first routing engines. Similarly, the secondrouting engines of the three or more router components are arranged in asecond fully connected topology whereby an input side of each one of thethree or more second routing engines includes a discrete link to aninput side of each one of the remaining ones of the three or more secondrouting engines. By interconnecting the input sides of the three or morerouting engines in this manner, all of the first routing engines willhave the same XN inputs, where X is the number of router componentsforming part of the linearly expandable router and N is the number ofinputs to each individual routing engine, and a backup routing engine inthe event of a failure thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a fully redundant linearly expandablebroadcast router constructed in accordance with the teachings of thepresent invention;

FIG. 2 is an expanded block diagram of a first broadcast routercomponent of the fully redundant linearly expandable broadcast router ofFIG. 1;

FIG. 3 is an expanded block diagram of a second broadcast routercomponent of the fully redundant linearly expandable broadcast router ofFIG. 1;

FIG. 4 is an expanded block diagram of a third broadcast routercomponent of the fully redundant linearly expandable broadcast router ofFIG. 1;

FIG. 5 is an expanded block diagram of a fourth broadcast routercomponent of the fully redundant linearly expandable broadcast router ofFIG. 1;

FIG. 6 is an expanded block diagram of a first expansion port of thefirst broadcast router component of FIG. 2;

FIG. 7 is an expanded block diagram of an alternate embodiment of thefirst broadcast router component of the fully redundant linearlyexpandable broadcast router of FIG. 1;

FIG. 8 is an expanded block diagram of an alternate embodiment of thesecond broadcast router component of the fully redundant linearlyexpandable broadcast router of FIG. 1;

FIG. 9 is an expanded block diagram of an alternate embodiment of thethird broadcast router component of the fully redundant linearlyexpandable broadcast router of FIG. 1; and

FIG. 10 is an expanded block diagram of an alternate embodiment of thefourth broadcast router component of the fully redundant linearlyexpandable broadcast router of FIG. 1.

DETAILED DESCRIPTION

Referring first to FIG. 1, a fully redundant linearly expandablebroadcast router 100 constructed in accordance with the teachings of thepresent invention will now be described in greater detail. As may now beseen, the fully redundant linearly expandable broadcast router 100 iscomprised of plural broadcast router components coupled to one anotherto form the larger fully redundant linearly expandable broadcast router100. Each broadcast router component is a discrete router device whichincludes first and second router matrices, the second router matrixbeing redundant of the first router matrix. Thus, each broadcast routerhas first and second routing engines, one for each of the first andsecond router matrices, each receiving, at an input side thereof, thesame input digital audio streams and placing, at an output side thereof,the same output digital audio streams. As disclosed herein, each of thebroadcast router components used to construct the fully redundantlinearly expandable broadcast router are N×M sized broadcast routers.However, it is fully contemplated that the fully redundant linearlyexpandable broadcast router 100 could instead be constructed ofbroadcast router components of different sizes relative to one another.

As further disclosed herein, the fully redundant linearly expandablebroadcast router 100 is formed by coupling together first, second, thirdand fourth broadcast router components 102, 104, 106 and 108. Of course,the present disclosure of the fully redundant linearly expandablebroadcast router 100 as being formed of four broadcast router componentsis purely by way of example. Accordingly, it should be clearlyunderstood that a fully redundant linearly expandable broadcast routerconstructed in accordance with the teachings of the present inventionmay be formed using various other numbers of broadcast router componentsas long as the total number of broadcast router components whichcollectively form the linearly expandable broadcast router is equal toor greater than three. The first, second, third and fourth broadcastrouter components 102, 104, 106 and 108 which, when fully connected inthe manner disclosed herein, collectively form the fully redundantlinearly expandable broadcast router 100, may either be housed togetherin a common chassis as illustrated in FIG. 1 or, if desired, housed inseparate chassis. While, as previously set forth, the broadcast routercomponents 102, 104, 106 and 108 may have different sizes relative toone another or, in the alternative, may all have the same N×M size, onesize that has proven suitable for the uses contemplated herein is256×256. Furthermore, a suitable configuration for the fully redundantlinear expandable broadcast router 100 would be to couple five broadcastrouter components, each sized at 256×256, thereby resulting in a1,280×1,280 broadcast router.

The first broadcast router component 102 is comprised of a first routermatrix 102 a and a second (or redundant) router matrix 102 b used toreplace the first router matrix 102 a in the event of a failure thereof.Similarly, each one of the second, third and fourth broadcast routercomponents 104, 106, and 108 of the fully redundant linearly expandablebroadcast router 100 are comprised of a first router matrix 104 a, 106 aand 108 a, respectively, and a second (or redundant) router matrix 104b, 106 b and 108 b, respectively, used to replace the first routermatrix 104 a, 106 a and 108 a, respectively, in the event of a failurethereof. Of course, the designation of the second router matrices 102 b,104 b, 106 b and 108 b as backups for the first router matrices 102 a,104 a, 106 a and 108 a, respectively, is purely arbitrary and it isfully contemplated that any either of a router matrix pair residingwithin a broadcast router component may act as a backup for the other ofthe router matrix pair residing within that broadcast router component.

As may be further seen in FIG. 1, the first router matrix 102 a of thefirst broadcast router component 102, the first router matrix 104 a ofthe second broadcast router component 104, the first router matrix 106 aof the third broadcast router component 106 and the first router matrix108 a of the fourth broadcast router component 108 are coupled togetherin a first arrangement of router matrices which conforms to a fullyconnected topology. Similarly, the second router matrix 102 b of thefirst broadcast router component 102, the second router matrix 104 b ofthe second broadcast router component 104, the second router matrix 106b of the third broadcast router component 106 and the second routermatrix 108 b of the fourth broadcast router component 108 are coupledtogether in a second arrangement which, like the first arrangement,conforms to a fully connected topology. In a fully connected topology,each router matrix of an arrangement of router matrices is coupled, by adiscrete link, to each and every other router matrix forming part of thearrangement of router matrices.

Thus, for the first arrangement of router matrices, first, second andthird bi-directional links 110, 112 and 114 couples the first routermatrix 102 a of the first broadcast router component 102 to the firstrouter matrix 104 a of the second broadcast router component 104, thefirst router matrix 106 a of the third broadcast router component 106and the first router matrix 108 a of the fourth broadcast routercomponent 108, respectively. Additionally, fourth and fifthbi-directional links 116 and 118 couple the first router matrix 104 a ofthe second broadcast router component 104 to the first router matrix 106a of the third broadcast router component 106 and the first routermatrix 108 a of the fourth broadcast router component 108, respectively.Finally, a sixth bi-directional link 120 couples the first router matrix106 a of the third broadcast router component 106 to the first routermatrix 108 a of the fourth broadcast router component 108. Variously,the bi-directional links 110 through 120 may be formed of copper wire,optical fiber or another transmission medium deemed suitable for theexchange of digital signals.

Similarly, for the second arrangement of router matrices, first, secondand third bi-directional links 122, 124 and 126 couples the secondrouter matrix 102 b of the first broadcast router component 102 to thesecond router matrix 104 b of the second broadcast router component 104,the second router matrix 106 b of the third broadcast router component106 and the second router matrix 108 b of the fourth broadcast routercomponent 108, respectively. Additionally, fourth and fifthbi-directional links 128 and 130 couple the second router matrix 104 bof the second broadcast router component 104 to the second router matrix106 b of the third broadcast router component 106 and the second routermatrix 108 b of the fourth broadcast router component 108, respectively.Finally, a sixth bi-directional link 132 couples the second routermatrix 106 b of the third broadcast router component 106 to the secondrouter matrix 108 b of the fourth broadcast router component 108. Again,the bi-directional links 122 through 132 may be formed of copper wire,optical fiber or another transmission medium deemed suitable for theexchange of digital signals.

Of course, rather than the single bi-directional links between pairs ofrouter matrices illustrated in FIG. 1, in an alternate embodiment of theinvention, it is contemplated that the pairs of router matrices mayinstead be coupled together by first and second uni-directional links.Such an alternate configuration is illustrated in each one of FIGS. 2-5.

Turning now to FIGS. 2-5, the fully redundant linearly expandablebroadcast router 100 will now be described in greater detail. The firstbroadcast router component 102 of the fully redundant linearlyexpandable broadcast router 100 is illustrated in FIG. 2. As may now beseen, the first broadcast router component is comprised of an input side134, an output side 136 and the first and second router matrices 102 aand 102 b, both of which are coupled between the input and output sides134 and 136. The input side 134 includes N selectors 138-1 through 138-Narranged such that the output of each one of the selectors provides oneof n inputs to the first and second router matrices 102 a and 102 b. Asdisclosed herein, each one of the selectors 138-1 through 138-N is a 2:1selector circuit having, as a first input 140-1 through 140-N,respectively, an input digital audio data stream conforming to the AudioEngineering Society-11 (“AES-11”) standard and, as a second input 142-1through 142-N, respectively, an input digital audio data streamconforming to the multichannel digital audio interface (“MADI”) standardset forth in the AES-10 standard. In this regard, it should be notedthat a MADI input digital audio data stream may contain up to 32 AESdigital audio data streams and that each one of the second inputs 142-1through 142-N contains a single AES digital audio data stream which hadpreviously been extracted from a MADI input digital audio data stream byextraction circuitry (not shown). Thus, the output of each one of theselector circuits 138-1 through 138-N provides one of N input digitalaudio data streams to each of the first and second router matrices 102 aand 102 b of the first broadcast router component 102. Each one of theselector circuits 138-1 through 138-N further includes a control input(not shown) for selecting between the AES-11 and MADI input digitalaudio data streams. Of course, it should be readily appreciated thatother types of input data streams other than the input digital audiodata streams disclosed herein are equally suitable for use with thefirst broadcast router component 102, as well as with the second, thirdand fourth broadcast router components 104, 106 and 108. For example, itis contemplated that the broadcast router components 102, 104, 106 and108 may instead be used with other low bandwidth digital signals such ascompressed video and data signals. It is further contemplated that, withminor modifications, for example, faster hardware, the broadcast routercomponents 102, 104, 106 and 108 may be used with non-compressed digitalvideo signals.

The selected input digital audio data stream output each one of theselector circuits 138-1 through 138-N is fed into a routing engine 144,a first expansion port 146, a second expansion port 148 and a thirdexpansion port 150 of the first router matrix 102 a. Additionally, theselected input digital audio data stream output each one of the selectorcircuits 138-1 through 138-N is fed into a routing engine 152, a firstexpansion port 154, a second expansion port 156 and a third expansionport 158 of the second router matrix 102 b. Residing within the routingengine 144 of the first router matrix 102 a is switching means forassigning any one of the input digital audio data signals received asinputs to the routing engine 144 to any one of the output lines of therouting engine 144. Variously, it is contemplated that the routingengine 144 may be embodied in software, for example, as a series ofinstructions; hardware, for example, as a series of logic circuits; or acombination thereof. In a broad sense, each one of the first, second andthird expansion ports 146, 148 and 150 of the first router matrix 102 ais comprised of a memory subsystem in which: (1) input digital audiodata streams received from the selector circuits 138-1 through 138-n ofa first broadcast router component; and (2) input digital audio datastreams received from an expansion port of a first router matrix of asecond broadcast router component may be buffered before transfer totheir final destination and a processor subsystem for controlling: (1)the transfer of the input digital audio data streams received from theselector circuits 138-1 through 138-N to an expansion port of the firstrouter matrix of another broadcast router component; and (2) thetransfer of the input digital audio data streams received from theexpansion port of the first router matrix of the other broadcast routercomponent to inputs of the routing engine 144 of the first router matrix102 a of the first broadcast router component 102. Similarly, residingwithin the routing engine 152 of the second router matrix 102 b isswitching means for assigning any one of the input digital audio datasignals received as inputs to the routing engine 152 to any one of theoutput lines of the routing engine 152. Again, it is contemplated thatthe routing engine 152 may be variously embodied in software, hardwareor a combination thereof. In a broad sense, each one of the first,second and third expansion ports 154 156 and 158 of the second routermatrix 102 b is comprised of a memory subsystem in which: (1) inputdigital audio data streams received from the selector circuits 138-1through 138-N of the first broadcast router component 102; and (2) inputdigital audio data streams received from an expansion port of a secondrouter matrix of the second broadcast router component may be bufferedbefore transfer to their final destination and a processor subsystem forcontrolling: (1) the transfer of the input digital audio data streamsreceived from the selector circuits 138-1 through 138-N to an expansionport of the second router matrix of the second broadcast routercomponent; and (2) the transfer of the input digital audio data streamsreceived from the expansion port of the second router matrix of thesecond broadcast router component to inputs of the routing engine 152 ofthe first router matrix 102 b of the first broadcast router component102.

Turning momentarily to FIG. 6, the expansion port 146 of the firstrouter matrix 102 a of the first broadcast router component 102 will nowbe described in greater detail. In this regard, it should be noted that,while only the first expansion port 130 is described and illustratedherein, second and third expansion ports 148 and 150 of the first routermatrix 102 a of the first broadcast router component 102, first, secondand third expansion ports 152, 154 and 156 of the second router matrix102 b of the first broadcast router component 102, first, second andthird expansion ports 180, 182 and 184 of the first router matrix 104 aof the second broadcast router component 104, first, second and thirdexpansion ports 188, 190 and 192 of the second router matrix 104 b ofthe second broadcast router component 104, first, second and thirdexpansion ports 214, 216 and 218 of the first router matrix 106 a of thethird broadcast router component 106, first, second and third expansionports 222, 224 and 226 of the second router matrix 106 b of the thirdbroadcast router component 106, first, second and third expansion ports248, 250 and 252 of the first router matrix 108 a of the fourthbroadcast router component 106 and first, second and third expansionports 256, 258 and 260 of the second router matrix 108 b of the fourthbroadcast router component 108 are similarly configured. Accordingly,the description that follows is equally applicable to those expansionports as well.

As may be seen in FIG. 6, the first expansion port 146 of the firstrouter matrix 102 a of the first broadcast router component 102 includesa first memory space 270 and a second memory space 272. Variously, thefirst and second memory spaces 270 and 272 may be comprised of first andsecond discrete memory devices or, as shown in FIG. 6, may be comprisedof first and second discrete address spaces within a common memorydevice. The expansion port 146 further includes control circuitry 274,for example, a controller, for controlling the transfer of input digitalaudio data streams, received by the expansion port 146, to their finaldestinations. More specifically, the input digital audio data streamoutput the selector circuit coupled to the expansion port 146, forexample, the selector circuit 138-1, is temporarily stored, or buffered,in the first memory space 270. The controller 274 then transfers thedigital audio data stored in the first memory space 270 to the secondmemory space 272 of the expansion port 180 of the first router matrix104 a of the second broadcast router component 104. Similarly, thedigital audio data stored in the first memory space 270 of the expansionport 180 of the first router matrix 104 a of the second broadcast routercomponent 104 is transferred to the second memory space 272. From thesecond memory space 272, the controller 274 provides the digital audiodata received from the second broadcast router component 104 as inputsto the routing engine 144 for the first router matrix 102 a of the firstbroadcast router component 102. Of course, the configuration andoperation of the expansion port 146 is but one device and processsuitable for the transfer of digital audio data and it is fullycontemplated that other devices and processes involving buffering and/orfirst-in-first-out (“FIFO”) schemes are equally suitable for thepurposes disclosed herein.

The second broadcast router component 104 of the fully redundantlinearly expandable broadcast router 100 is illustrated in FIG. 3. Asmay now be seen, the second broadcast router component 104 is comprisedof an input side 168, an output side 170 and the first and second routermatrices 104 a and 104 b, both of which are coupled between the inputand output sides 202 and 204. The input side 202 includes N selectors176-1 through 176-N arranged such that the output of each one of theselectors provides one of N inputs to the first and second routermatrices 104 a and 104 b. As disclosed herein, each one of the selectors176-1 through 176-N is a 2:1 selector circuit having, as a first input172-1 through 172-N, respectively, an input digital audio data streamconforming to the AES-11 standard and, as a second input 174-1 through174-N, respectively, an input digital audio data stream conforming tothe MADI standard. Again, it should be noted that a MADI input digitalaudio data stream may contain up to 32 AES digital audio data streamsand that each one of the second inputs 174-1 through 174-N contains asingle AES digital audio data stream which had previously been extractedfrom a MADI input digital audio data stream by extraction circuitry (notshown). Thus, the output of each one of the selector circuits 176-1through 176-N provides one of N input digital audio data streams to eachof the first and second router matrices 104 a and 104 b of the secondbroadcast router component 104. Each one of the selector circuits 176-1through 176-N further includes a control input (not shown) for selectingbetween the AES-11 and MADI input digital audio data streams.

The selected input digital audio data stream output each one of theselector circuits 176-1 through 176-N is fed into a routing engine 178,a first expansion port 180, a second expansion port 182 and a thirdexpansion port 184 of the first router matrix 104 a. Additionally, theselected input digital audio data stream output each one of the selectorcircuits 176-1 through 176-N is fed into a routing engine 186, a firstexpansion port 188, a second expansion port 190 and a third expansionport 192 of the second router matrix 102 b. Residing within the routingengine 178 of the first router matrix 104 a is switching means forassigning any one of the input digital audio data signals received asinputs to the routing engine 178 to any one of the output lines of therouting engine 178. Variously, it is contemplated that the routingengine 178 may be embodied in software, hardware or a combinationthereof. In a broad sense, each one of the first, second and thirdexpansion ports 180, 182 and 184 of the first router matrix 104 a iscomprised of a memory subsystem in which: (1) input digital audio datastreams received from the selector circuits 176-1 through 176-N of afirst broadcast router component; and (2) input digital audio datastreams received from an expansion port of a first router matrix of asecond broadcast router component may be buffered before transfer totheir final destination and a processor subsystem for controlling: (1)the transfer of the input digital audio data streams received from theselector circuits 176-1 through 176-N to an expansion port of the firstrouter matrix of another broadcast router component; and (2) thetransfer of the input digital audio data streams received from theexpansion port of the first router matrix of the other broadcast routercomponent to inputs of the routing engine 178 of the first router matrix104 a of the second broadcast router component 104.

Similarly, residing within the routing engine 186 of the second routermatrix 104 b is switching means for assigning any one of the inputdigital audio data signals received as inputs to the routing engine 186to any one of the output lines of the routing engine 186. Again, it iscontemplated that the routing engine 186 may be variously embodied insoftware, hardware or a combination thereof. In a broad sense, each oneof the first, second and third expansion ports 188, 190 and 192 of thesecond router matrix 104 b is comprised of a memory subsystem in which:(1) input digital audio data streams received from the selector circuits176-1 through 176-N of the second broadcast router component 104; and(2) input digital audio data streams received from an expansion port ofa second router matrix of another broadcast router component may bebuffered before transfer to their final destination and a processorsubsystem for controlling: (1) the transfer of the input digital audiodata streams received from the selector circuits 176-1 through 176-N toan expansion port of the second router matrix of the other broadcastrouter component; and (2) the transfer of the input digital audio datastreams received from the expansion port of the second router matrix ofthe other broadcast router component to inputs of the routing engine 186of the second router matrix 104 b of the second broadcast routercomponent 104.

The third broadcast router component 106 of the fully redundant linearlyexpandable broadcast router 100 is illustrated in FIG. 4. As may now beseen, the third broadcast router component 106 is comprised of an inputside 202, an output side 204 and the first and second router matrices106 a and 106 b, both of which are coupled between the input and outputsides 202 and 204. The input side 202 includes N selectors 210-1 through210-N arranged such that the output of each one of the selectorsprovides one of N inputs to the first and second router matrices 106 aand 106 b. As disclosed herein, each one of the selectors 210-1 through210-N is a 2:1 selector circuit having, as a first input 206-1 through206-N, respectively, an input digital audio data stream conforming tothe AES-11 standard and, as a second input 208-1 through 208-N,respectively, an input digital audio data stream conforming to the MADIstandard. In this regard, it is again noted that a MADI input digitalaudio data stream may contain up to 32 AES digital audio data streamsand that each one of the second inputs 208-1 through 208-N contains asingle AES digital audio data stream which had previously been extractedfrom a MADI input digital audio data stream by extraction circuitry (notshown). Thus, the output of each one of the selector circuits 210-1through 210-N provides one of N input digital audio data streams to eachof the first and second router matrices 106 a and 106 b of the thirdbroadcast router component 106. Each one of the selector circuits 210-1through 210-N further includes a control input (not shown) for selectingbetween the AES-11 and MADI input digital audio data streams.

The selected input digital audio data stream output each one of theselector circuits 210-1 through 210-n is fed into a routing engine 212,a first expansion port 214, a second expansion port 216 and a thirdexpansion port 218 of the first router matrix 106 a. Additionally, theselected input digital audio data stream output each one of the selectorcircuits 210-1 through 210-N is fed into a routing engine 220, a firstexpansion port 222, a second expansion port 224 and a third expansionport 226 of the second router matrix 106 b. Residing within the routingengine 212 of the first router matrix 106 a is switching means forassigning any one of the input digital audio data signals received asinputs to the routing engine 212 to any one of the output lines of therouting engine 212. Variously, it is contemplated that the routingengine 144 may be embodied in software, hardware, or a combinationthereof. In a broad sense, each one of the first, second and thirdexpansion ports 214, 216 and 218 of the first router matrix 106 a iscomprised of a memory subsystem in which: (1) input digital audio datastreams received from the selector circuits 210-1 through 210-N of thethird broadcast router component 106; and (2) input digital audio datastreams received from an expansion port of a first router matrix ofanother broadcast router component may be buffered before transfer totheir final destination and a processor subsystem for controlling: (1)the transfer of the input digital audio data streams received from theselector circuits 210-1 through 210-N to an expansion port of the firstrouter matrix of the other broadcast router component; and (2) thetransfer of the input digital audio data streams received from theexpansion port of the first router matrix of the other broadcast routercomponent to inputs of the routing engine 212 of the first router matrix106 a of the third broadcast router component 106. Similarly, residingwithin the routing engine 220 of the second router matrix 106 b isswitching means for assigning any one of the input digital audio datasignals received as inputs to the routing engine 220 to any one of theoutput lines of the routing engine 220. Again, it is contemplated thatthe routing engine 220 may be variously embodied in software, hardwareor a combination thereof. In a broad sense, each one of the first,second and third expansion ports 222, 224 and 226 of the second routermatrix 106 b is comprised of a memory subsystem in which: (1) inputdigital audio data streams received from the selector circuits 210-1through 210-N of the first broadcast router component 106; and (2) inputdigital audio data streams received from an expansion port of a secondrouter matrix of the other broadcast router component may be bufferedbefore transfer to their final destination and a processor subsystem forcontrolling: (1) the transfer of the input digital audio data streamsreceived from the selector circuits 210-1 through 210-N to an expansionport of the second router matrix of the other broadcast routercomponent; and (2) the transfer of the input digital audio data streamsreceived from the expansion port of the second router matrix of theother broadcast router component to inputs of the routing engine 220 ofthe second router matrix 106 b of the third broadcast router component106.

The fourth broadcast router component 108 of the fully redundantlinearly expandable broadcast router 100 is illustrated in FIG. 5. Asmay now be seen, the fourth broadcast router component 108 is comprisedof an input side 236, an output side 238 and the first and second routermatrices 108 a and 108 b, both of which are coupled between the inputand output sides 236 and 238. The input side 236 includes n selectors244-1 through 244-N arranged such that the output of each one of theselectors provides one of n inputs to the first and second routermatrices 108 a and 108 b. As disclosed herein, each one of the selectors244-1 through 244-N is a 2:1 selector circuit having, as a first input240-1 through 240-N, respectively, an input digital audio data streamconforming to the AES-11 standard and, as a second input 242-1 through242-N, respectively, an input digital audio data stream conforming tothe MADI standard. Thus, the output of each one of the selector circuits244-1 through 244-N provides one of N input digital audio data streamsto each of the first and second router matrices 108 a and 108 b for thefourth broadcast router component 108. Each one of the selector circuits244-1 through 244-N further includes a control input (not shown) forselecting between the AES-11 and MADI input digital audio data streams.

The selected input digital audio data stream output each one of theselector circuits 244-1 through 244-N is fed into a routing engine 246,a first expansion port 248, a second expansion port 250 and a thirdexpansion port 252 of the first router matrix 108 a. Additionally, theselected input digital audio data stream output each one of the selectorcircuits 244-1 through 244-N is fed into a routing engine 254, a firstexpansion port 256, a second expansion port 258 and a third expansionport 260 of the second router matrix 108 b. Residing within the routingengine 246 of the first router matrix 108 a is switching means forassigning any one of the input digital audio data signals received asinputs to the routing engine 246 to any one of the output lines of therouting engine 246. Variously, it is contemplated that the routingengine 246 may be embodied in software, hardware, or a combinationthereof. In a broad sense, each one of the first, second and thirdexpansion ports 248, 250 and 252 of the fourth router matrix 108 a iscomprised of a memory subsystem in which: (1) input digital audio datastreams received from the selector circuits 244-1 through 244-N of afirst broadcast router component; and (2) input digital audio datastreams received from an expansion port of a first router matrix ofanother broadcast router component may be buffered before transfer totheir final destination and a processor subsystem for controlling: (1)the transfer of the input digital audio data streams received from theselector circuits 244-1 through 244-N to an expansion port of the firstrouter matrix of the other broadcast router component; and (2) thetransfer of the input digital audio data streams received from theexpansion port of the first router matrix of the other broadcast routercomponent to inputs of the routing engine 246 of the first router matrix108 a of the fourth broadcast router component 108. Similarly, residingwithin the routing engine 254 of the second router matrix 108 b isswitching means for assigning any one of the input digital audio datasignals received as inputs to the routing engine 254 to any one of theoutput lines of the routing engine 254. Again, it is contemplated thatthe routing engine 254 may be variously embodied in software, hardwareor a combination thereof. In a broad sense, each one of the first,second and third expansion ports 256, 258 and 260 of the second routermatrix 108 b is comprised of a memory subsystem in which: (1) inputdigital audio data streams received from the selector circuits 244-1through 244-n of the fourth broadcast router component 108; and (2)input digital audio data streams received from an expansion port of asecond router matrix of the other broadcast router component may bebuffered before transfer to their final destination and a processorsubsystem for controlling: (1) the transfer of the input digital audiodata streams received from the selector circuits 244-1 through 244-N toan expansion port of the second router matrix of the other broadcastrouter component; and (2) the transfer of the input digital audio datastreams received from the expansion port of the second router matrix ofthe other broadcast router component to inputs of the routing engine 254of the second router matrix 108 b of the fourth broadcast routercomponent 108.

Referring next to FIGS. 2-5, as a discrete input digital audio datastream is output each of the selector circuits 138-1 through 138-N, theinput digital audio data streams fed to each one of the input side ofthe routing engine 144, the first expansion port 146, the secondexpansion port 148 and the third expansion port 150 of the first routermatrix 102 a of the first broadcast router component 102 are audio datainput streams 1 through N. Similarly, the input digital audio datastreams fed to each one of the input side of the routing engine 178, thefirst expansion port 180, the second expansion port 182 and the thirdexpansion port 184 of the first router matrix 104 a of the secondbroadcast router component 104 are input digital audio data streams N+1through 2N; the input digital audio data streams fed to each one of theinput side of the routing engine 212, the first expansion port 214, thesecond expansion port 216 and the third expansion port 218 of the firstrouter matrix of the third broadcast router component 106 are inputdigital audio data streams 2N+1 through 3N; and the input digital audiodata streams fed to each one of the input side of the routing engine246, the first expansion port 248, the second expansion port 250 and thethird expansion port 252 of the first router matrix 108 a of the fourthbroadcast router component 108 are input digital audio data streams 3N+1through 4N.

To function as a 4N×4M broadcast router, the routing engine 144 of thefirst router matrix 102 a of the first broadcast router component 102,the routing engine 178 of the second router matrix 104 a of the secondbroadcast router component 104, the routing engine 212 of the thirdrouter matrix 106 a of the third broadcast router component 106 and therouting engine 246 of the fourth router matrix 108 a 8 of the fourthbroadcast router component 108 must have all of the input digital audiodata streams 1 through 4N provided as inputs to the input side thereof.For the routing engine 144 of the first router matrix 102 a of the firstbroadcast router component 102, the input digital audio data streams 1through N are provided to the input side of the routing engine 144directly. The input digital audio data streams 1 through N input thefirst, second and third expansion ports 146, 148 and 150, on the otherhand, are transferred to the first expansion port 180 of the firstrouter matrix 104 a of the second broadcast router component 104 overthe link 110, the second expansion port 216 of the first router matrix106 b of the third broadcast router component 106 over the link 112 andthe third expansion port 252 of the first router matrix 108 a of thefourth broadcast router component 108 over the link 114, respectively.From the first expansion port 180 of the first router matrix 104 a ofthe second broadcast router component 104, the second expansion port 216of the first router matrix 106 a of the third broadcast router component106 and the third expansion port 252 of the first router matrix 108 a ofthe fourth broadcast router component 108, the input digital audio datastreams 1 through N are input the routing engine 178 of the first routermatrix 104 a of the second broadcast router component 104, the routingengine 212 of the first router matrix 106 a of the third broadcastrouter component 106 and the routing engine 246 of the first routermatrix 108 a of the fourth broadcast router components 108,respectively.

Similarly, for the first router matrix 104 a of the second broadcastrouter component 104, the input digital audio data streams N+1 through2N are provided to the input side of the routing engine 178 directly.The input digital audio data streams N+1 through 2N input the first,second and third expansion ports 180, 182 and 184, on the other hand,are transferred to the first expansion port 130 of the first routermatrix 102 a of the broadcast router component 102 over the link 110,the first expansion port 214 of the first router matrix 106 a of thethird broadcast router component 106 over the link 116 and the secondexpansion port 250 of the first router matrix 108 a of the fourthbroadcast router component 108 over the link 118, respectively. From thefirst expansion port 180 of the first router matrix 102 a of the firstbroadcast router component 102, the first expansion port 214 of thefirst router matrix 106 a of the third broadcast router component 106and the second expansion port 250 of the first router matrix 108 a ofthe fourth broadcast router component 108, the input digital audio datastreams N+1 through 2N are input the routing engine 144 of the firstrouting matrix 102 a of the first broadcast router component 102, therouting engine 212 of the first routing matrix 106 a of the thirdbroadcast router component 106 and the routing engine 246 of the firstrouting matrix 108 a of the fourth router component 108; respectively.

For the first router matrix 106 a of the third broadcast routercomponent 106, the input digital audio data streams 2N+1 through 3N areinput the routing engine 212 directly. The input digital audio datastreams 2N+1 through 3N input the first, second and third expansionports 214, 216 and 218, on the other hand, are transferred to the secondexpansion port 182 of the first router matrix 104 a of the secondbroadcast router component 104 over the link 116, the second expansionport 148 of the first router matrix 102 a of the first broadcast routercomponent 102 over the link 112 and the first expansion port 248 of thefirst router matrix 108 a of the fourth broadcast router component 108over the link 120, respectively. From the second expansion port 182 ofthe first router matrix 104 a of the second broadcast router component104, the second expansion port 148 of the first router matrix 102 a ofthe first broadcast router component 102 and the first expansion port248 of the first router matrix 108 a of the fourth broadcast routercomponent 108, the input digital audio data streams 2N+1 through 3N areinput the routing engine 144 of the first router matrix 102 a of thefirst broadcast router 102, the routing engine 178 of the first routermatrix 104 a of the second broadcast router 104 and the routing engine246 of the first router matrix 108 a of the fourth broadcast routercomponent 108.

Finally, for the first router matrix 108 a of the fourth broadcastrouter component 108, the input digital audio data streams 3N+1 through4N are input the routing engine 246 directly. The input digital audiodata streams 3N+1 through 4N input the first, second and third expansionports 248, 250 and 252, on the other hand, are transferred to the thirdexpansion port 218 of the first router matrix 106 a of the thirdbroadcast router component 106 over the link 120, the third expansionport 184 of the first router matrix 104 a of the second broadcast routercomponent 104 over the link 118 and the third expansion port 150 of thefirst router matrix 102 a of the broadcast router component 102 over thelink 114, respectively. From the third expansion port 150 of the firstrouter matrix 102 a of the first broadcast router component 102, thethird expansion port 184 of the first router matrix 104 a of the secondbroadcast router component 104 and the third expansion port 218 of thefirst router matrix 106 a of the third broadcast router component 106,the input digital audio data streams 3N+1 through 4N are input therouting engine 144 of the first routing matrix 102 a of the firstbroadcast router component 102, the routing engine 178 of the firstrouting matrix 104 a of the second broadcast router component 104 andthe routing engine 212 of the first routing matrix 106 a of the thirdbroadcast router component 106. In this manner, the routing engine 144of the first router matrix 102 a of the first broadcast router component102, the routing engine 178 of the first router matrix 104 a of thesecond broadcast router component 104, the routing engine 212 of thefirst router matrix 106 a of the third broadcast router component 106and the routing engine 246 of the first router matrix 108 a of thefourth broadcast router component 108 all receive, as inputs thereto,the input digital audio data streams 1 through 4N.

Within the routing engine 144 of the first router matrix 102 a of thefirst broadcast router component 102, switch logic or other switchingmeans enables any one of the input digital audio data streams 1 through4N to be applied to any of the 1 through M outputs thereof. Similarly,switch logic or other switching means within the routing engine 178 ofthe first router matrix 104 a of the second broadcast router component104, the routing engine 212 of the first router matrix 106 a of thethird broadcast router component and the routing engine 246 of the firstrouter matrix 108 a of the fourth router component 108 enables any oneof the input digital audio data streams 1 through 4N to be applied toany of the M+1 through 2M, 2M+1 through 3M and 3M+1 through 4M outputsthereof, respectively. The switching logic or other switching meanswithin each of the routing engines 144, 178, 212, and 246 is controlledby one or more control inputs which originate at a controller (notshown) or other control circuitry for the linearly expandable broadcastrouter 100.

As previously set forth, the second router matrices 102 b, 104 b, 106 band 108 b are redundant router matrices available for use in the eventthat the respective one or ones of the first router matrices 102 a, 104a, 106 a and 108 a fail. To function as redundant matrices, the secondrouter matrices 102 b, 104 b, 106 b and 108 b must receive/transmit thesame input/output digital audio data streams as the corresponding one ofthe first router matrices 102 a, 104 a, 106 a and 108 a. Accordingly,the selector circuits 138-1 through 138-N also feed input digital audiodata streams 1 through N to each one of the routing engine 152, thefirst expansion port 154, the second expansion port 156 and the thirdexpansion port 158 of the second router matrix 102 b of the firstbroadcast router component 102. Similarly, the selector circuits 176-1through 176-N also feed input digital audio data streams N+1 through 2Nto each one of the routing engine 186, the first expansion port 188, thesecond expansion port 190 and the third expansion port 192 of the secondrouter matrix 104 b of the second broadcast router component 104; theselector circuits 210-1 through 210-N also feed input digital audio datastreams 2N+1 through 3N to each one of the routing engine 220, the firstexpansion port 222, the second expansion port 224 and the thirdexpansion port 226 of the second router matrix 106 b of the thirdbroadcast router component 106; and the selector circuits 244-1 through244-N also feed input digital audio data streams 3N+1 through 4N to eachone of the routing engine 254, the first expansion port 256, the secondexpansion port 258 and the third expansion port 260 of the second routermatrix 108 b of the fourth broadcast router component 108.

The routing engine 152 of the second router matrix 102 b of the firstbroadcast router component 102, the routing engine 186 of the secondrouter matrix 104 b of the second broadcast router component 104, therouting engine 220 of the second router matrix 106 b of the thirdbroadcast router component 106 and the routing engine 254 of the secondrouter matrix 108 b of the fourth broadcast router component 108 musthave all of the input digital audio data streams 1 through 4N providedas inputs thereto. For the routing engine 152 of the second routermatrix 102 b of the first broadcast router component 102, the selectorcircuits 138-1 through 138-N provide input digital audio data streams 1through N as inputs thereto. The input digital audio data streams 1through N input the first, second and third expansion ports 154, 156 and158, on the other hand, are transferred to the first expansion port 188of the second router matrix 104 b of the second broadcast routercomponent 104 over the link 122, the second expansion port 224 of thesecond router matrix 106 b of the third broadcast router component 106over the link 124 and the third expansion port 260 of the second routermatrix 108 b of the fourth broadcast router component 108 over the link126, respectively. From the first expansion port 188 of the secondrouter matrix 104 b of the second broadcast router component 104, thesecond expansion port 224 of the second router matrix 106 b of the thirdbroadcast router component 106 and the third expansion port 260 of thesecond router matrix 108 b of the fourth broadcast router component 108,the input digital audio data streams 1 through N are input the routingengine 186 of the second router matrix 104 b of the second broadcastrouter component 104, the routing engine 220 of the second router matrix106 b of the third broadcast router component 106 and the routing engine254 of the second router matrix 108 b of the fourth broadcast routercomponents 108, respectively.

Similarly, for the second router matrix 104 b of the second broadcastrouter component 104, the input digital audio data streams N+1 through2N are directly input the routing engine 186. The input digital audiodata streams N+1 through 2N input the first, second and third expansionports 188, 190 and 192, on the other hand, are transferred to the firstexpansion port 154 of the second router matrix 102 b of the broadcastrouter component 102 over the link 122, the first expansion port 222 ofthe second router matrix 106 b of the third broadcast router component106 over the link 128 and the second expansion port 258 of the secondrouter matrix 108 b of the fourth broadcast router component 108 overthe link 130, respectively. From the first expansion port 154 of thesecond router matrix 102 b of the first broadcast router component 102,the first expansion port 222 of the second router matrix 106 b of thethird broadcast router component 106 and the second expansion port 258of the second router matrix 108 b of the fourth broadcast routercomponent 108, the input digital audio data streams N+1 through 2N areinput the routing engine 152 of the second routing matrix 102 b of thefirst broadcast router component 102, the routing engine 220 of thesecond routing matrix 106 b of the third broadcast router component 106and the routing engine 254 of the second routing matrix 108 a of thefourth router component 108, respectively.

For the second router matrix 106 b of the third broadcast routercomponent 106, the input digital audio data streams 2N+1 through 3N areinput the routing engine 220 directly. The input digital audio datastreams 2N+1 through 3N input the first, second and third expansionports 222, 224 and 226, on the other hand, are transferred to the secondexpansion port 190 of the second router matrix 104 b of the secondbroadcast router component 104 over the link 128, the second expansionport 156 of the second router matrix 102 b of the first broadcast routercomponent 102 over the link 126 and the first expansion port 256 of thesecond router matrix 108 b of the fourth broadcast router component 108over the link 132, respectively. From the second expansion port 190 ofthe second router matrix 104 b of the second broadcast router component104, the second expansion port 156 of the second router matrix 102 b ofthe first broadcast router component 102 and the first expansion port256 of the second router matrix 108 b of the fourth broadcast routercomponent 108, the input digital audio data streams 2N+1 through 3N areinput the routing engine 152 of the second router matrix 102 b of thefirst broadcast router 102, the routing engine 186 of the second routermatrix 104 b of the second broadcast router 104 and the routing engine254 of the second router matrix 108 b of the fourth broadcast routercomponent 108.

Finally, for the second router matrix 108 b of the fourth broadcastrouter component 108, the input digital audio data streams 3N+1 through4N are input the routing engine 254 directly. The input digital audiodata streams 3N+1 through 4N input the first, second and third expansionports 256, 258 and 260, on the other hand, are transferred to the thirdexpansion port 226 of the second router matrix 106 b of the thirdbroadcast router component 106 over the link 132, the third expansionport 192 of the second router matrix 104 b of the second broadcastrouter component 104 over the link 130 and the second expansion port 156of the second router matrix 102 b of the broadcast router component 102over the link 126, respectively. From the second expansion port 156 ofthe second router matrix 102 b of the first broadcast router component102, the third expansion port 192 of the second router matrix 104 b ofthe second broadcast router component 104 and the third expansion port226 of the second router matrix 106 b of the third broadcast routercomponent 106, the input digital audio data streams 3N+1 through 4N areinput the routing engine 152 of the second routing matrix 102 b of thefirst broadcast router component 102, the routing engine 186 of thesecond routing matrix 104 b of the second broadcast router component 104and the routing engine 220 of the second routing matrix 106 b of thethird broadcast router component 106. In this manner, the routing engine152 of the second router matrix 102 b of the first broadcast routercomponent 102, the routing engine 186 of the second router matrix 104 bof the second broadcast router component 104, the routing engine 220 ofthe second router matrix 106 b of the third broadcast router component106 and the routing engine 254 of the second router matrix 108 b of thefourth broadcast router component 108 all receive, as inputs thereto,the input digital audio data streams 1 through 4N.

Within the routing engine 152 of the second router matrix 102 b of thefirst broadcast router component 102, switch logic or other switchingmeans enables any one of the input digital audio data streams 1 through4N to be applied to any of the 1 through M outputs thereof. Similarly,switch logic or other switching means within the routing engine 186 ofthe second router matrix 104 b of the second broadcast router component104, the routing engine 220 of the second router matrix 106 b of thethird broadcast router component and the routing engine 254 of thesecond router matrix 108 b of the fourth router component 108 enablesany one of the input digital audio data streams 1 through 4N to beapplied to any of the M+1 through 2M, 2M+1 through 3M and 3M+1 through4M outputs thereof, respectively. The switching logic or other switchingmeans within each of the routing engines 152, 186, 220, and 254 iscontrolled by one or more control inputs which originate at a controller(not shown) or other control circuitry for the fully redundant linearlyexpandable broadcast router 100.

Each one of the 1 through M digital audio data streams output therouting engines 144 and 152 of the first and second routing matrices 102a and 102 b, respectively, of the first broadcast router component 102are propagated to a corresponding one of first selector circuits 160-1through 160-M. The first selector circuits 160-1 through 160-Mcollectively determine whether the 1 through m digital audio datastreams output the routing engine 144 of the first routing matrix 102 aor the 1 through M digital audio data streams output the routing engine152 of the second routing matrix 102 b shall be the output of the firstbroadcast router component 102. Each one of the first selector circuits160-1 through 160-M share a common control input (not shown) forselecting whether the digital audio data streams output the routingengine 144 or the digital audio data streams output the routing engine152 shall be passed by the first selector circuits 160-1 through 160-M.

Similarly, each one of the M+1 through 2M digital audio data streamsoutput the routing engines 178 and 186 of the first and second routingmatrices 104 a and 104 b, respectively, of the second broadcast routercomponent 104 are propagated to corresponding ones of first selectorcircuits 228-1 through 228-M. The first selector circuits 228-1 through228-M collectively determine whether the 1 through M digital audio datastreams output the routing engine 178 of the first routing matrix 104 aor the 1 through M digital audio data streams output the routing engine186 of the second routing matrix 104 b shall be the output of the secondbroadcast router component 104. Each one of the first selector circuits228-1 through 228-M share a common control input (not shown) forselecting whether the digital audio data streams output the routingengine 178 or the digital audio data streams output the routing engine186 shall be passed by the first selector circuits 228-1 through 228-M.

Similarly again, each one of the 2M+1 through 3M digital audio datastreams output the routing engines 212 and 220 of the first and secondrouting matrices 106 a and 106 b, respectively, of the third broadcastrouter component 106 are propagated to corresponding ones of firstselector circuits 228-1 through 228-M. The first selector circuits 228-1through 228-M collectively determine whether the 2M+1 through 3M digitalaudio data streams output the routing engine 212 of the first routingmatrix 106 a or the 2M+1 through 3M digital audio data streams outputthe routing engine 220 of the second routing matrix 106 b shall be theoutput of the third broadcast router component 106. Each one of thefirst selector circuits 228-1 through 228-M share a common control input(not shown) for selecting whether the digital audio data streams outputthe routing engine 212 or the digital audio data streams output therouting engine 220 shall be passed by the first selector circuits 228-1through 228-M.

Finally, each one of the 3M+1 through 4M digital audio data streamsoutput the routing engines 246 and 254 of the first and second routingmatrices 108 a and 108 b, respectively, of the fourth broadcast routercomponent 108 are propagated to corresponding ones of first selectorcircuits 262-1 through 262-M. The first selector circuits 262-1 through262-M collectively determine whether the 3M+1 through Mm digital audiodata streams output the routing engine 246 of the first routing matrix108 a or the 3M+1 through 4M digital audio data streams output therouting engine 256 of the second routing matrix 108 b shall be theoutput of the fourth broadcast router component 104. Each one of thefirst selector circuits 262-1 through 262-M share a common control input(not shown) for selecting whether the digital audio data streams outputthe routing engine 246 or the digital audio data streams output therouting engine 254 shall be passed by the first selector circuits 262-1through 262-M.

Thus, in the foregoing manner, each one of the first, second, third andfourth broadcast router components 102, 104, 106 and 108 has a routermatrix pair, specifically, the router matrix pairs 102 a and 102 b, 104a and 104 b, 106 a and 106 b, and 108 a and 108 b, configured such thata first one of the router matrix pair may readily function as a back-upto a second one of the router matrix pair in the event of a failurethereof. To switch between the first and second ones of the routermatrix pair, for example, to switch from the first router matrix 102 ato the second router matrix 102 b, the common control input to thecorresponding first selector circuits 160-1 through 160-M, which hadbeen previously set such that the output of the first router matrix 102a is passed by the selector circuits 160-1 through 160-M, is switchedbetween states such that the first selector circuits 160-1 through 160-Mshall now pass the output of the second router matrix 102 b.

Each one of the 1 through M, M+1 through 2M, 2M+1 through 3M and 3M+1through 4M digital audio data streams passed by the first selectorcircuits 160-1 through 160-M, 194-1 through 194-M, 228-1 through 228-Mand 262-1 through 262-M, respectively, are then propagated to acorresponding second selector circuit 162-1 through 162-M, 196-1 through196-M, 230-1 through 230-M and 264-1 through 264-M. As disclosed herein,each one of the second selector circuits 162-1 through 162-M, 196-1through 196-M, 230-1 through 230-M and 264-1 through 264-M is a 1:2selector circuit having an input coupled to a corresponding output ofthe first selector circuit 160-1 through 160-M, 194-1 through 194-M,228-1 through 228-M and 262-1 through 262-M, a first output 164-1through 164-M, 198-1 through 198-M, 232-1 through 232-M and 266-1through 266-M configured to transmit an output digital audio data streamconforming to the AES-11 standard and a second output 166-1 through166-m, 200-1 through 200-M, 234-1 through 234-M and 268-1 through 268-Mconfigured to transmit an output digital audio data stream conforming tothe MADI standard. Each one of the second selector circuits 162-1through 162-M, 196-1 through 196-M, 230-1 through 230-M and 264-1through 264-M further includes a control input (not shown) for selectingbetween the AES-11 and MADI output digital audio data streams.

In an alternate embodiment of the invention not shown in the drawings,the selector circuits 138-1 through 138-N, 176-1 through 175-N, 210-1through 210-N, 244-1 through 244-N, 162-1 through 162-M, 196-1 through196-M, 230-1 through 230-M and 264-1 through 264-M may be omitted if thebroadcast router components 102, 104, 106 and 108 are instead configuredto handle input digital audio data streams conforming to a singlestandard, for example, the AES-11 standard, the MADI standard or anotherstandard not specifically recited herein. In accordance with thisconfiguration, however, each of the N input digital audio data streamsfor the first broadcast router component 102 would be fed directly tothe routing engine 144, first expansion port 146, second expansion port148 and third expansion port 150 of the first router matrix 102 a andthe routing engine 152, first expansion port 154, second expansion port156 and third expansion port 158 of the second router matrix 102 b.Similarly, each of the N input digital audio data streams for the secondbroadcast router component 104 would be fed directly to the routingengine 178, first expansion port 180, second expansion port 182 andthird expansion port 184 of the first router matrix 104 a and therouting engine 186, first expansion port 188, second expansion port 190and third expansion port 192 of the second router matrix 104. Similarlyagain, each of the N input digital audio data streams for the thirdbroadcast router component 106 would be fed directly to the routingengine 212, the first expansion port 214, the second expansion port 216and the third expansion port 218 of the first router matrix 106 a andthe routing engine 220, the first expansion port 222, the secondexpansion port 224 and the third expansion port 226 of the second routermatrix 106 b. Finally, each of the N input digital audio data streamsfor the fourth broadcast router component 108 would be fed directly tothe routing engine 246, the first expansion port 248, the secondexpansion port 250 and the third expansion port 252 of the first routermatrix 108 a and the routing engine 254, the first expansion port 256,the second expansion port 258 and the third expansion port 260 of thesecond router matrix 108 b. In further accordance with this alternateembodiment of the invention, each of the M output digital audio datastreams output the first selector circuits 160-1 through 160-M, 194-1through 194-M, 228-1 through 228-M and 262-1 through 262-M of the first,second, third and fourth broadcast router components 102, 104, 106 and108, respectively, would be outputs of the fully redundant linearlyexpandable broadcast router 100 itself.

Referring next to FIGS. 7-10, an alternate configuration of thebroadcast router components of the fully redundant linearly expandablebroadcast router 100 will now be described in greater detail. Morespecifically, for each of the first, second, third and fourth broadcastrouter components 102, 104, 106 and 108, the first, second and thirdexpansion ports have been removed in favor of a transmitting expansionport, a first receiving expansion port, a second receiving expansionport and a third receiving expansion port. By the term “transmitting”expansion port, it is intended to refer to an expansion port from whichdata is transmitted to a selected destination. Similarly, by the term“receiving” expansion port, it is intended to refer to an expansion portwhich receives data from a destination.

The alternate configuration of the first broadcast router component 102may be seen in FIG. 7. As may now be seen, the first router matrix 102 ais now comprised of the routing engine 144, a transmitting expansionport 276, a first receiving expansion port 278, a second receivingexpansion port 280 and a third receiving expansion port 282. Similarly,the second router matrix 102 b is comprised of the routing engine 152, atransmitting expansion port 284, a first receiving expansion port 286, asecond receiving expansion port 288 and a third receiving expansion port290. In a broad sense, the transmitting expansion port 276 of the firstrouter matrix 102 a is comprised of a memory subsystem in which inputdigital audio data streams received from the selector circuits 140-1through 140-N of the first broadcast router component 102 are bufferedbefore transfer to plural destinations and a processor subsystem forcontrolling the transfer of the input digital audio data streamsreceived from the selector circuits 140-1 through 140-N to a receivingexpansion port of the first router matrix 104 a of the second broadcastrouter component 104, a receiving expansion port of the first routermatrix 106 a of the third broadcast router component 106 and a receivingexpansion port of the first router matrix 108 a of the fourth broadcastrouter component 108. Conversely, each one of the first, second andthird expansion ports 278, 280 and 282 of the first router matrix 102 aare, in a broad sense, comprised of a memory subsystem in which inputdigital audio data streams received from a transmitting expansion portof the first router matrix of another broadcast router component may bebuffered before transfer to their final destination and a processorsubsystem for controlling the transfer of the input digital audio datastreams received from the transmitting expansion port of the firstrouter matrix of the other broadcast router component to inputs of therouting engine 144 of the first router matrix 102 a of the firstbroadcast router component 102.

Similarly, in one sense, the transmitting expansion port 276 of thesecond router matrix 102 b is comprised of a memory subsystem in whichinput digital audio data streams received from the selector circuits140-1 through 140-N of the first broadcast router component 102 arebuffered before transfer to plural destinations and a processorsubsystem for controlling the transfer of the input digital audio datastreams received from the selector circuits 140-1 through 140-N to areceiving expansion port of the second router matrix 104 a of the secondbroadcast router component 104, a receiving expansion port of the secondrouter matrix 106 b of the third broadcast router component 106 and areceiving expansion port of the second router matrix 108 b of the fourthbroadcast router component 108. Conversely, each one of the first,second and third expansion ports 278, 280 and 282 of the second routermatrix 102 b are, in one aspect, comprised of a memory subsystem inwhich input digital audio data streams received from a transmittingexpansion port of the second router matrix of another broadcast routercomponent may be buffered before transfer to their final destination anda processor subsystem for controlling the transfer of the input digitalaudio data streams received from the transmitting expansion port of thesecond router matrix of the other broadcast router component to inputsof the routing engine 144 of the second router matrix 102 b of the firstbroadcast router component 102.

The alternate configuration of the second broadcast router component 104may be seen in FIG. 8. As may now be seen, the first router matrix 104 ais now comprised of the routing engine 178, a transmitting expansionport 292, a first receiving expansion port 294, a second receivingexpansion port 296 and a third receiving expansion port 298. Similarly,the second router matrix 102 b is comprised of the routing engine 186, atransmitting expansion port 300, a first receiving expansion port 302, asecond receiving expansion port 304 and a third receiving expansion port306. In a broad sense, the transmitting expansion port 292 of the firstrouter matrix 104 a is comprised of a memory subsystem in which inputdigital audio data streams received from the selector circuits 172-1through 172-N of the second broadcast router component 104 are bufferedbefore transfer to plural destinations and a processor subsystem forcontrolling the transfer of the input digital audio data streamsreceived from the selector circuits 172-1 through 172-N to a receivingexpansion port of the first router matrix 102 a of the first broadcastrouter component 102, a receiving expansion port of the first routermatrix 106 a of the third broadcast router component 106 and a receivingexpansion port of the first router matrix 108 a of the fourth broadcastrouter component 108. Conversely, each one of the first, second andthird expansion ports 294, 296 and 298 of the first router matrix 104 aare, in a broad sense, comprised of a memory subsystem in which inputdigital audio data streams received from a transmitting expansion portof the first router matrix of another broadcast router component may bebuffered before transfer to their final destination and a processorsubsystem for controlling the transfer of the input digital audio datastreams received from the transmitting expansion ports of the firstrouter matrix of the other broadcast router components to inputs of therouting engine 178 of the first router matrix 104 a of the secondbroadcast router component 102.

Similarly, in one sense, the transmitting expansion port 300 of thesecond router matrix 104 b of the second broadcast router component 104is comprised of a memory subsystem in which input digital audio datastreams received from the selector circuits 172-1 through 172-N of thesecond broadcast router component 104 are buffered before transfer toplural destinations and a processor subsystem for controlling thetransfer of the input digital audio data streams received from theselector circuits 172-1 through 172-N to a receiving expansion port ofthe second router matrix 102 b of the first broadcast router component102, the second router matrix 106 b of the third broadcast routercomponent 106 and the second router matrix 108 b of the fourth broadcastrouter component 108. Conversely, each one of the first, second andthird expansion ports 303, 304 and 306 of the second router matrix 104 bare, in one aspect, comprised of a memory subsystem in which inputdigital audio data streams received from an transmission expansion portof the second router matrix of another broadcast router component may bebuffered before transfer to their final destination and a processorsubsystem for controlling the transfer of the input digital audio datastreams received from the transmitting expansion port of the secondrouter matrix of the other broadcast router component to inputs of therouting engine 186 of the second router matrix 104 b of the secondbroadcast router component 104.

The alternate configuration of the third broadcast router component 106may be seen in FIG. 9. As may now be seen, the first router matrix 106 ais now comprised of the routing engine 212, a transmitting expansionport 308, a first receiving expansion port 310, a second receivingexpansion port 312 and a third receiving expansion port 314. Similarly,the second router matrix 106 b is comprised of the routing engine 220, atransmitting expansion port 316, a first receiving expansion port 318, asecond receiving expansion port 320 and a third receiving expansion port322. In a broad sense, the transmitting expansion port 308 of the firstrouter matrix 106 a is comprised of a memory subsystem in which inputdigital audio data streams received from the selector circuits 210-1through 210-N of the third broadcast router component 106 are bufferedbefore transfer to plural destinations and a processor subsystem forcontrolling the transfer of the input digital audio data streamsreceived from the selector circuits 210-1 through 210-N to a receivingexpansion port of the first router matrix 102 a of the first broadcastrouter component 102, a receiving expansion port of the first routermatrix 104 a of the second broadcast router component 104 and areceiving expansion port of the first router matrix 108 a of the fourthbroadcast router component 108. Conversely, each one of the first,second and third expansion ports 310, 312 and 314 of the first routermatrix 106 a are, in a broad sense, comprised of a memory subsystem inwhich input digital audio data streams received from a transmittingexpansion port of the first router matrix of another broadcast routercomponent may be buffered before transfer to their final destination anda processor subsystem for controlling the transfer of the input digitalaudio data streams received from the transmitting expansion ports of thefirst router matrix of the other broadcast router components to inputsof the routing engine 212 of the first router matrix 106 a of the thirdbroadcast router component 106.

Similarly, in one sense, the transmitting expansion port 316 of thesecond router matrix 106 b of the third broadcast router component 106is comprised of a memory subsystem in which input digital audio datastreams received from the selector circuits 210-1 through 210-N of thethird broadcast router component 106 are buffered before transfer toplural destinations and a processor subsystem for controlling thetransfer of the input digital audio data streams received from theselector circuits 210-1 through 210-N to a receiving expansion port ofthe second router matrix 102 b of the first broadcast router component102, a receiving expansion port of the second router matrix 104 b of thesecond broadcast router component 104 and the second router matrix 108 bof the fourth broadcast router component 108. Conversely, each one ofthe first, second and third expansion ports 318, 320 and 322 of thesecond router matrix 106 b are, in one aspect, comprised of a memorysubsystem in which input digital audio data streams received from atransmission expansion port of the second router matrix of anotherbroadcast router component may be buffered before transfer to theirfinal destination and a processor subsystem for controlling the transferof the input digital audio data streams received from the transmittingexpansion port of the second router matrix of the other broadcast routercomponent to inputs of the routing engine 220 of the second routermatrix 106 b of the third broadcast router component 106.

The alternate configuration of the fourth broadcast router component 108may be seen in FIG. 10. As may now be seen, the first router matrix 108a is now comprised of the routing engine 246, a transmitting expansionport 324, a first receiving expansion port 326, a second receivingexpansion port 328 and a third receiving expansion port 330. Similarly,the second router matrix 108 b is comprised of the routing engine 254, atransmitting expansion port 332, a first receiving expansion port 334, asecond receiving expansion port 336 and a third receiving expansion port338. In a broad sense, the transmitting expansion port 324 of the firstrouter matrix 108 a is comprised of a memory subsystem in which inputdigital audio data streams received from the selector circuits 244-1through 244-N of the fourth broadcast router component 108 are bufferedbefore transfer to plural destinations and a processor subsystem forcontrolling the transfer of the input digital audio data streamsreceived from the selector circuits 244-1 through 244-N to a receivingexpansion port of the first router matrix 102 a of the first broadcastrouter component 102, a receiving expansion port of the first routermatrix 104 a of the second broadcast router component 104 and areceiving expansion port of the first router matrix 106 a of the thirdbroadcast router component 106. Conversely, each one of the first,second and third expansion ports 326, 328 and 330 of the first routermatrix 108 a are, in a broad sense, comprised of a memory subsystem inwhich input digital audio data streams received from a transmittingexpansion port of the first router matrix of another broadcast routercomponent may be buffered before transfer to their final destination anda processor subsystem for controlling the transfer of the input digitalaudio data streams received from the transmitting expansion ports of thefirst router matrix of the other broadcast router components to inputsof the routing engine 246 of the first router matrix 108 a of the fourthbroadcast router component 108.

Similarly, in one sense, the transmitting expansion port 332 of thesecond router matrix 108 b of the fourth broadcast router component 108is comprised of a memory subsystem in which input digital audio datastreams received from the selector circuits 244-1 through 244-N of thefourth broadcast router component 108 are buffered before transfer toplural destinations and a processor subsystem for controlling thetransfer of the input digital audio data streams received from theselector circuits 244-1 through 244-N to a receiving expansion port ofthe second router matrix 102 ba of the first broadcast router component102, the second router matrix 104 b of the second broadcast routercomponent 104 and the second router matrix 106 b of the third broadcastrouter component 106. Conversely, each one of the first, second andthird expansion ports 334, 336 and 338 of the second router matrix 108 bare, in one aspect, comprised of a memory subsystem in which inputdigital audio data streams received from a transmission expansion portof the second router matrix of another broadcast router component may bebuffered before transfer to their final destination and a processorsubsystem for controlling the transfer of the input digital audio datastreams received from the transmitting expansion port of the secondrouter matrix of the other broadcast router component to inputs of therouting engine 254 of the second router matrix 108 b of the fourthbroadcast router component 108.

Referring next to FIGS. 7-10, as a discrete input digital audio datastream is output each of the selector circuits 138-1 through 138-N, theinput digital audio data streams fed to the routing engine 144 and theexpansion transmission port 276 of the first router matrix 102 a of thefirst broadcast router component 102 are audio data input streams 1through N. Similarly, the input digital audio data streams fed to therouting engine 178 and the transmission expansion port 292 of the firstrouter matrix 104 a of the second broadcast router component 104 areinput digital audio data streams N+1 through 2N; the input digital audiodata streams fed to the routing engine 212 and the transmissionexpansion port 308 of the first router matrix 106 a of the thirdbroadcast router component 106 are input digital audio data streams 2N+1through 3N; and the input digital audio data streams fed to each one ofthe routing engine 246 and the transmission expansion port 324 of thefirst router matrix 108 a of the fourth broadcast router component 108are input digital audio data streams 3N+1 through 4N.

As before, to function as a 4N×4M broadcast router, the routing engine144 of the first router matrix 102 a of the first broadcast routercomponent 102, the routing engine 178 of the second router matrix 104 aof the second broadcast router component 104, the routing engine 212 ofthe third router matrix 106 a of the third broadcast router component106 and the routing engine 246 of the fourth router matrix 108 a of thefourth broadcast router component 108 must have all of the input digitalaudio data streams 1 through 4N provided as inputs to the input sidethereof. For the routing engine 144 of the first router matrix 102 a ofthe first broadcast router component 102, the input digital audio datastreams 1 through N are provided to the input side of the routing engine144 directly. The input digital audio data streams 1 through N input thetransmitting expansion port 276, on the other hand, are transferred tothe first receiving expansion port 294 of the first router matrix 104 aof the second broadcast router component 104 over the link 110, thesecond receiving expansion port 312 of the first router matrix 106 b ofthe third broadcast router component 106 over the link 112 and thesecond receiving expansion port 330 of the first router matrix 108 a ofthe fourth broadcast router component 108 over the link 114,respectively. From the first receiving expansion port 294 of the firstrouter matrix 104 a of the second broadcast router component 104, thesecond receiving expansion port 312 of the first router matrix 106 a ofthe third broadcast router component 106 and the second receivingexpansion port 330 of the first router matrix 108 a of the fourthbroadcast router component 108, the input digital audio data streams 1through N are input the routing engine 178 of the first router matrix104 a of the second broadcast router component 104, the routing engine212 of the first router matrix 106 a of the third broadcast routercomponent 106 and the routing engine 246 of the first router matrix 108a of the fourth broadcast router components 108, respectively.

Similarly, for the first router matrix 104 a of the second broadcastrouter component 104, the input digital audio data streams N+1 through 2n are provided to the input side of the routing engine 178 directly. Theinput digital audio data streams N+1 through 2N input the transmittingexpansion port 292, on the other hand, are transferred to each of thefirst receiving expansion port 278 of the first router matrix 102 a ofthe broadcast router component 102 over the link 110, the firstreceiving expansion port 310 of the first router matrix 106 a of thethird broadcast router component 106 over the link 116 and the secondreceiving expansion port 328 of the first router matrix 108 a of thefourth broadcast router component 108 over the link 118, respectively.From the first receiving expansion port 278 of the first router matrix102 a of the first broadcast router component 102, the first receivingexpansion port 310 of the first router matrix 106 a of the thirdbroadcast router component 106 and the second receiving expansion port328 of the first router matrix 108 a of the fourth broadcast routercomponent 108, the input digital audio data streams N+1 through 2N areinput the routing engine 144 of the first routing matrix 102 a of thefirst broadcast router component 102, the routing engine 212 of thefirst routing matrix 106 a of the third broadcast router component 106and the routing engine 246 of the first routing matrix 108 a of thefourth router component 108, respectively.

For the first router matrix 106 a of the third broadcast routercomponent 106, the input digital audio data streams 2N+1 through 3N areinput the routing engine 212 directly. The input digital audio datastreams 2N+1 through 3N input the transmitting expansion ports 308, onthe other hand, is transferred to each of the second receiving expansionport 296 of the first router matrix 104 a of the second broadcast routercomponent 104 over the link 116, the second receiving expansion port 280of the first router matrix 102 a of the first broadcast router component102 over the link 112 and the first receiving expansion port 326 of thefirst router matrix 108 a of the fourth broadcast router component 108over the link 120, respectively. From the second receiving expansionport 296 of the first router matrix 104 a of the second broadcast routercomponent 104, the second receiving expansion port 280 of the firstrouter matrix 102 a of the first broadcast router component 102 and thefirst receiving expansion port 326 of the first router matrix 108 a ofthe fourth broadcast router component 108, the input digital audio datastreams 2N+1 through 3N are input the routing engine 144 of the firstrouter matrix 102 a of the first broadcast router 102, the routingengine 178 of the first router matrix 104 a of the second broadcastrouter 104 and the routing engine 246 of the first router matrix 108 aof the fourth broadcast router component 108.

Finally, for the first router matrix 108 a of the fourth broadcastrouter component 108, the input digital audio data streams 3N+1 through4N are input the routing engine 246 directly. The input digital audiodata streams 3N+1 through 4N input the transmitting expansion port 324,on the other hand, is transferred to each one of the third receivingexpansion port 314 of the first router matrix 106 a of the thirdbroadcast router component 106 over the link 120, the third receivingexpansion port 298 of the first router matrix 104 a of the secondbroadcast router component 104 over the link 118 and the third receivingexpansion port 282 of the first router matrix 102 a of the broadcastrouter component 102 over the link 114, respectively. From the thirdreceiving expansion port 282 of the first router matrix 102 a of thefirst broadcast router component 102, the third receiving expansion port298 of the first router matrix 104 a of the second broadcast routercomponent 104 and the third receiving expansion port 314 of the firstrouter matrix 106 a of the third broadcast router component 106, theinput digital audio data streams 3N+1 through 4N are input the routingengine 144 of the first routing matrix 102 a of the first broadcastrouter component 102, the routing engine 178 of the first routing matrix104 a of the second broadcast router component 104 and the routingengine 212 of the first routing matrix 106 a of the third broadcastrouter component 106. In this manner, the routing engine 144 of thefirst router matrix 102 a of the first broadcast router component 102,the routing engine 178 of the first router matrix 104 a of the secondbroadcast router component 104, the routing engine 212 of the firstrouter matrix 106 a of the third broadcast router component 106 and therouting engine 246 of the first router matrix 108 a of the fourthbroadcast router component 108 all receive, as inputs thereto, the inputdigital audio data streams 1 through 4N.

In this embodiment as well, the second router matrices 102 b, 104 b, 106b and 108 b are redundant router matrices available for use in the eventthat the respective one or ones of the first router matrices 102 a, 104a, 106 a and 108 a fail. To function as redundant matrices, the secondrouter matrices 102 b, 104 b, 106 b and 108 b must receive/transmit thesame input/output digital audio data streams as the corresponding one ofthe first router matrices 102 a, 104 a, 106 a and 108 a. Accordingly,the selector circuits 138-1 through 138-N also feed input digital audiodata streams 1 through N to each of the routing engine 152 and the firsttransmitting expansion port 284 of the second router matrix 102 b of thefirst broadcast router component 102. Similarly, the selector circuits176-1 through 176-N also feed input digital audio data streams N+1through 2N to each of the routing engine 186 and the transmittingexpansion port 300 of the second router matrix 104 b of the secondbroadcast router component 104; the selector circuits 210-1 through210-N also feed input digital audio data streams 2N+1 through 3N to eachof the routing engine 220 and the transmitting expansion port 316 of thesecond router matrix 106 b of the third broadcast router component 106;and the selector circuits 244-1 through 244-n also feed input digitalaudio data streams 3N+1 through 4N to each of the routing engine 254 andthe transmitting expansion port 332 of the second router matrix 108 b ofthe fourth broadcast router component 108.

Also as before, the routing engine 152 of the second router matrix 102 bof the first broadcast router component 102, the routing engine 186 ofthe second router matrix 104 b of the second broadcast router component104, the routing engine 220 of the second router matrix 106 b of thethird broadcast router component 106 and the routing engine 254 of thesecond router matrix 108 b of the fourth broadcast router component 108must have all of the input digital audio data streams 1 through 4Nprovided as inputs thereto. For the routing engine 152 of the secondrouter matrix 102 b of the first broadcast router component 102, theselector circuits 138-1 through 138-N provide input digital audio datastreams 1 through N as inputs thereto. The input digital audio datastreams 1 through N input the transmitting expansion port 284, on theother hand, is transferred to each of the first receiving expansion port306 of the second router matrix 104 b of the second broadcast routercomponent 104 over the link 122, the second receiving expansion port 320of the second router matrix 106 b of the third broadcast routercomponent 106 over the link 124 and the first receiving expansion port334 of the second router matrix 108 b of the fourth broadcast routercomponent 108 over the link 126, respectively. From the first receivingexpansion port 306 of the second router matrix 104 b of the secondbroadcast router component 104, the second receiving expansion port 320of the second router matrix 106 b of the third broadcast routercomponent 106 and the first receiving expansion port 334 of the secondrouter matrix 108 b of the fourth broadcast router component 108, theinput digital audio data streams 1 through N are input the routingengine 186 of the second router matrix 104 b of the second broadcastrouter component 104, the routing engine 220 of the second router matrix106 b of the third broadcast router component 106 and the routing engine254 of the second router matrix 108 b of the fourth broadcast routercomponents 108, respectively.

Similarly, for the second router matrix 104 b of the second broadcastrouter component 104, the input digital audio data streams N+1 through2N are directly input the routing engine 186. The input digital audiodata streams N+1 through 2N input the transmitting expansion port 300,on the other hand, is transferred to each one of the third receivingexpansion port 290 of the second router matrix 102 b of the firstbroadcast router component 102 over the link 122, the third receivingexpansion port 322 of the second router matrix 106 b of the thirdbroadcast router component 106 over the link 128 and the secondreceiving expansion port 336 of the second router matrix 108 b of thefourth broadcast router component 108 over the link 130, respectively.From the third receiving expansion port 290 of the second router matrix102 b of the first broadcast router component 102, the third receivingexpansion port 322 of the second router matrix 106 b of the thirdbroadcast router component 106 and the second receiving expansion port336 of the second router matrix 108 b of the fourth broadcast routercomponent 108, the input digital audio data streams N+1 through 2N areinput the routing engine 152 of the second routing matrix 102 b of thefirst broadcast router component 102, the routing engine 220 of thesecond routing matrix 106 b of the third broadcast router component 106and the routing engine 254 of the second routing matrix 108 a of thefourth router component 108, respectively.

For the second router matrix 106 b of the third broadcast routercomponent 106, the input digital audio data streams 2N+1 through 3N areinput the routing engine 220 directly. The input digital audio datastreams 2N+1 through 3N input the transmitting expansion port 316, onthe other hand, is transferred to each one of the second receivingexpansion port 304 of the second router matrix 104 b of the secondbroadcast router component 104 over the link 128, the first receivingexpansion port 286 of the second router matrix 102 b of the firstbroadcast router component 102 over the link 124 and the third receivingexpansion port 338 of the second router matrix 108 b of the fourthbroadcast router component 108 over the link 132, respectively. From thesecond receiving expansion port 304 of the second router matrix 104 b ofthe second broadcast router component 104, the first receiving expansionport 286 of the second router matrix 102 b of the first broadcast routercomponent 102 and the third receiving expansion port 338 of the secondrouter matrix 108 b of the fourth broadcast router component 108, theinput digital audio data streams 2N+1 through 3N are input the routingengine 152 of the second router matrix 102 b of the first broadcastrouter 102, the routing engine 186 of the second router matrix 104 b ofthe second broadcast router 104 and the routing engine 254 of the secondrouter matrix 108 b of the fourth broadcast router component 108.

Finally, for the second router matrix 108 b of the fourth broadcastrouter component 108, the input digital audio data streams 3N+1 through4N are input the routing engine 254 directly. The input digital audiodata streams 3N+1 through 4N input the transmitting expansion port 332,on the other hand, is transferred to each one of the first receivingexpansion port 318 of the second router matrix 106 b of the thirdbroadcast router component 106 over the link 132, the first receivingexpansion port 302 of the second router matrix 104 b of the secondbroadcast router component 104 over the link 130 and the secondreceiving expansion port 288 of the second router matrix 102 b of thefirst broadcast router component 102 over the link 126, respectively.From the second receiving expansion port 288 of the second router matrix102 b of the first broadcast router component 102, the first receivingexpansion port 302 of the second router matrix 104 b of the secondbroadcast router component 104 and the first receiving expansion port318 of the second router matrix 106 b of the third broadcast routercomponent 106, the input digital audio data streams 3N+1 through 4N areinput the routing engine 152 of the second routing matrix 102 b of thefirst broadcast router component 102, the routing engine 186 of thesecond routing matrix 104 b of the second broadcast router component 104and the routing engine 220 of the second routing matrix 106 b of thethird broadcast router component 106. In this manner, the routing engine152 of the second router matrix 102 b of the first broadcast routercomponent 102, the routing engine 186 of the second router matrix 104 bof the second broadcast router component 104, the routing engine 220 ofthe second router matrix 106 b of the third broadcast router component106 and the routing engine 254 of the second router matrix 108 b of thefourth broadcast router component 108 all receive, as inputs thereto,the input digital audio data streams 1 through 4N. Further processing ofthe input digital audio streams 1 through 4N will then proceed in themanner hereinabove described with respect to FIGS. 2-5.

Thus, there has been disclosed and illustrated herein a robust linearlyexpandable broadcast router which, by employing a fully connectedtopology between the plural broadcast router components forming thelinearly expandable broadcast router, enjoys improved fault toleranceover prior linearly expandable broadcast routers using plural busstructures to interconnect the plural broadcast router components.Further, by eliminating redundant links, the linearly expandablebroadcast router represents an economical and cost-effective solution tomany broadcast router needs. While preferred embodiments of thisinvention have been shown and described herein, various modificationsand other changes can be made by one skilled in the art to which theinvention pertains without departing from the spirit or teaching of thisinvention. Accordingly, the scope of protection is not limited to theembodiments described herein, but is only limited by the claims thatfollow.

1. An expandable router for routing a signal from at least one input toone or more outputs, comprising: at least X routing components, where Xis an integer greater than two, each of the X routing components havingfirst and second routing engines, each routing engine having M inputsand N outputs where M and N are integers both greater than one, eachrouting engine routing a signal from one of the M inputs to one or moreof the N outputs; each first routing engine of each of the X routingcomponents having its inputs coupled by first links in a first fullyconnected topology to inputs of others of the first routing engines ofthe X routing components; each second routing engine of each of the Xrouting components having its inputs coupled by second links in a secondfully connected topology to inputs of others of the second routingengines of the X routing components, wherein said second links aredifferent from said first links; wherein the coupling of the inputs ofthe inputs of the routing engines affords the routing engines with acommon set of XM inputs, with each of the first and second routingengines in each routing component serving as a backup to the other ofthe routing engines in the same routing component.
 2. The routeraccording to claim 1 wherein the links between inputs of each routingengine of a routing component and inputs of a routing engine of anotherrouting component are bi-directional.
 3. The router according to claim 1wherein the links between inputs of each routing engine of a routingcomponent and inputs of a routing engine of another routing componentcomprise pairs of unidirectional links.
 4. The router according to claim1 wherein each routing component further comprises first and secondexpansion modules.
 5. The router according to claim 4 wherein eachexpansion module comprises first and second memories each capable ofstoring data received at the expansion module.
 6. The method accordingto claim 5 wherein each expansion module further includes a controllerfor transferring data between the first and second memories.